1. Field of the Invention
The present invention relates to a photosensitive resin composition, a method of forming patterns using the composition, a photosensitive liquid for forming colored images, and a color filter.
2. Description of the Related Art
The necessity of a photosensitive resin with excellent stability and photosensitivity has extremely increased in a pattern formation process during manufacture of semiconductor devices as well as in a process of manufacturing a color filter for use in liquid crystal displays and image devices. Such a resin is also required to have good resistance to heat that is applied during the process of manufacturing it and when it is used.
Various photosensitive resins have heretofore been proposed and employed in practice. A photosensitive polyimide resin has recently received attention, because of such advantages that it can be patterned without a photoresist to produce a physically and chemically stable layer with excellent heat resistance after it is cured.
Photosensitive polyimide resins have a photosensitive group introduced into a soluble polyamic acid that is a precursor of polyimide. Other photosensitive polyimide resins have a photosensitive group directly introduced into a solublized polyimide. In either case, there are a lot of resins that have properties of the photocuring type, or negative type. A positive photosensitive polyimide resin having an o-nitrobenzyl group introduced therein is also reported as a polyimide precursor.
There is also proposed another positive photosensitive resin that has a specific metal complex added in an acrylic, phenolic, polyester or polyurethane resin (JP-10-153863A).
The above-mentioned photosensitive polyimide resin has a structure in which a photosensitive group is introduced into a polyimide resin precursor. In negative resins, a light-illuminated part becomes insoluble. On the other hand, in positive resins, a light-illuminated part becomes soluble and thus the resin can advantageously be patterned without a photoresist.
A colorant such as a dye or pigment is added into a conventional photosensitive polyimide resin to produce color filters. Some colorants added, however, inhibit the crosslinking reaction of photosensitive groups and cause the fading of the filters. That is, some color filters are insufficient in light resistance and poor in aging resistance. Therefore, it is desired to develop photosensitive polyimide resins improved in these properties.
Accordingly, a first aspect of the present invention is to provide a photosensitive resin composition excellent particularly in stability and photosensitivity.
A second aspect of the present invention is to provide a method of forming a pattern using such a photosensitive resin composition.
A third aspect of the present invention is a photosensitive liquid for forming colored images with excellent light resistance.
A fourth aspect of the present invention is a color filter using such a photosensitive resin composition.
In accordance with the present invention, there is provided a photosensitive resin composition, which comprises a resin having a carboxyl group in the molecule and an arene compound represented by the following formula (1):
[(Ar)(CpM)2]2+2Xxe2x88x92xe2x80x83xe2x80x83(1)
wherein Ar denotes an aromatic xcfx80-arene capable of coordinating with at least two metalcyclopentadienyl compounds; Cp denotes an anion of cyclopentadiene; M denotes a metal cation; and Xxe2x88x92 denotes any one selected from the group consisting of SbF6xe2x88x92, BF4xe2x88x92, AsF6xe2x88x92 and PF6xe2x88x92.
In accordance with the present invention, there is also provided a method of forming a pattern, which comprises applying the above-mentioned photosensitive resin composition onto a substrate, drying the composition at a temperature of 100xc2x0 C. or below to produce a resinous coating, exposing the coating for a given pattern to form an exposed coating, heating the exposed coating at a temperature of 100-170xc2x0 C., and carrying out development.
In accordance with the present invention, there is further provided the above-mentioned photosensitive liquid, which comprises a resin having a carboxyl group in the molecule, an arene compound represented by the following formula (2):
[(Ar)(CpM)n]n+nXxe2x88x92xe2x80x83xe2x80x83(2)
wherein Ar denotes an aromatic compound; M denotes a metal cation; Cp denotes an anion of cyclopentadiene; X denotes an anion; and n denotes a positive integer; a colorant; and a solvent.
According to the present invention, there is still further provided a color filter having a pattern. The pattern is formed by applying the above-mentioned photosensitive liquid onto a substrate; drying the liquid to produce a resinous coating; exposing the coating for a given pattern; baking and then carrying out development.